<div dir="ltr"><div>Hi Pavan, <br></div><div><br></div><div>I am not an expert on CP2K code, but in a theoretical point of view what you want to calculate is the same state, just in a different micro-state. <br></div><div>The case you show, or what ever case of duplet spin multiplicity has two micro-states (in the spin freedom degree), and both have the same energy (degenerated) and are described by the same spectroscopic term, but with different z spin projection. In both cases the quantum state for all properties is the same (except for Ŝ_z), then most of program, for simplicity, uses the alpha channel to project the spin.</div><div>For higher spin multiplicities, you have more micro-states for the same spectroscopic term, but is complex in some cases. The triplet example, you have 3 micro-states, S_z=+1,0,-1. The former and the latter are a single determinant and the only difference is the channels of the unpaired electrons (two), is a simple case as duplet multiplicity, but, the S_z=0 case is complex, due to this state is a linear combination of two determinants, and needs multi reference description. Then the full spin projection is a simpler case.</div><div><br></div><div>Only if you use a magnetic field, the degeneration is broken, and both cases you mention are differents.</div><div><br></div><div>Regards - Lucas Lodeiro<br></div><div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">El jue., 16 abr. 2020 a las 17:38, pavan kumar behara (<<a href="mailto:pavan...@gmail.com">pavan...@gmail.com</a>>) escribió:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div><span style="font-family:verdana,sans-serif">Hello CP2K developers,</span></div><div><span style="font-family:verdana,sans-serif"><br></span></div><div><span style="font-family:verdana,sans-serif">I notice that excess electrons are always assigned to alpha channel, is it possible to generate a configuration where I can have more beta electrons?</span><span style="font-family:verdana,sans-serif"> Let's consider a minimal example of hydrogen molecule with excess charge, H-H(-), making it a 3-electron system. I can always calculate [2 spin-up, 1 spin-down] configuration<br></span><div class="gmail_default" style="font-size:small;color:rgb(0,0,0)"> <table style="border-collapse:collapse;border:medium none;margin-left:6.75pt;margin-right:6.75pt" cellspacing="0" cellpadding="0" border="1" align="left"> <tbody><tr style="height:14.6pt"> <td style="width:23pt;border:1pt solid windowtext;padding:0in 5.4pt;height:14.6pt" width="31" valign="top"> <p class="MsoNormal" style="margin:0in 0in 0.0001pt;text-align:center;line-height:normal;font-size:11pt" align="center"><span style="font-family:verdana,sans-serif"><span style="color:red">↑</span><span style="color:red"><span></span></span></span></p> </td> <td style="width:30.75pt;border-color:windowtext windowtext windowtext currentcolor;border-style:solid solid solid none;border-width:1pt 1pt 1pt medium;padding:0in 5.4pt;height:14.6pt" width="41" valign="top"> <p class="MsoNormal" style="margin:0in 0in 0.0001pt;text-align:center;line-height:normal;font-size:11pt" align="center"><span style="font-family:verdana,sans-serif"><span style="color:red">↑</span><b><span style="color:rgb(0,112,192)">↓</span></b><span style="color:red"><span></span></span></span></p> </td> </tr> </tbody></table> </div><div class="gmail_default" style="font-size:small;color:rgb(0,0,0)"><span style="font-family:verdana,sans-serif"><br></span></div><div class="gmail_default" style="font-size:small;color:rgb(0,0,0)"><span style="font-family:verdana,sans-serif"><br></span></div><div class="gmail_default" style="font-size:small;color:rgb(0,0,0)"><span style="font-family:verdana,sans-serif">but never [1 spin-up, 2 spin-down]<br></span></div><div class="gmail_default" style="font-size:small;color:rgb(0,0,0)"> <table style="border-collapse:collapse;border:medium none;margin-left:6.75pt;margin-right:6.75pt" cellspacing="0" cellpadding="0" border="1" align="left"> <tbody><tr style="height:14.6pt"> <td style="width:23pt;border:1pt solid windowtext;padding:0in 5.4pt;height:14.6pt" width="31" valign="top"> <p class="MsoNormal" style="margin:0in 0in 0.0001pt;text-align:center;line-height:normal;font-size:11pt" align="center"><span style="font-family:verdana,sans-serif"><span style="color:rgb(0,112,192)">↓</span><span style="color:rgb(0,112,192)"><span></span></span></span></p> </td> <td style="width:30.75pt;border-color:windowtext windowtext windowtext currentcolor;border-style:solid solid solid none;border-width:1pt 1pt 1pt medium;padding:0in 5.4pt;height:14.6pt" width="41" valign="top"> <p class="MsoNormal" style="margin:0in 0in 0.0001pt;text-align:center;line-height:normal;font-size:11pt" align="center"><span style="font-family:verdana,sans-serif"><span style="color:rgb(0,112,192)">↓</span><b><span style="color:red">↑</span></b><span style="color:rgb(0,112,192)"><span></span></span></span></p> </td> </tr> </tbody></table> </div><div><span style="font-family:verdana,sans-serif"><br></span></div><div><span style="font-family:verdana,sans-serif"><br></span></div><div style="font-size:small;color:rgb(0,0,0)" class="gmail_default"><span style="font-family:verdana,sans-serif">I started with a spin-down hydrogen as initial atomic guess but the density matrix is re-scaled before starting the SCF iterations making it 2 alpha and 1 beta. <br></span></div><div style="font-size:small;color:rgb(0,0,0)" class="gmail_default"><span style="font-family:verdana,sans-serif"><br></span></div><div style="font-size:small;color:rgb(0,0,0)" class="gmail_default"><span style="font-family:verdana,sans-serif">Is there a way to get the second configuration or there is a reason not to do so? I attached the inputs and output for your reference.</span></div><div style="font-size:small;color:rgb(0,0,0)" class="gmail_default"><span style="font-family:verdana,sans-serif"><br></span></div><div style="font-size:small;color:rgb(0,0,0)" class="gmail_default"><span style="font-family:verdana,sans-serif">Any help is appreciated, thank you very much for your time.</span></div><div style="font-size:small;color:rgb(0,0,0)" class="gmail_default"><span style="font-family:verdana,sans-serif"><br></span></div><div style="font-size:small;color:rgb(0,0,0)" class="gmail_default"><span style="font-family:verdana,sans-serif"><br></span></div><div style="font-size:small;color:rgb(0,0,0)" class="gmail_default"><span style="font-family:verdana,sans-serif">Best regards,</span></div><div style="font-size:small;color:rgb(0,0,0)" class="gmail_default"><span style="font-family:verdana,sans-serif">Pavan.<br></span></div><div style="font-size:small;color:rgb(0,0,0)" class="gmail_default"><span style="font-family:verdana,sans-serif"><br></span></div><div style="font-size:small;color:rgb(0,0,0)" class="gmail_default"><span style="font-family:verdana,sans-serif"><img alt=""><img alt=""><img alt=""><img alt=""></span></div></div></div> <p></p> -- <br> You received this message because you are subscribed to the Google Groups "cp2k" group.<br> To unsubscribe from this group and stop receiving emails from it, send an email to <a href="mailto:cp...@googlegroups.com" target="_blank">cp...@googlegroups.com</a>.<br> To view this discussion on the web visit <a href="https://groups.google.com/d/msgid/cp2k/631dd3cc-55b5-4d01-854b-c2255130c39b%40googlegroups.com?utm_medium=email&utm_source=footer" target="_blank">https://groups.google.com/d/msgid/cp2k/631dd3cc-55b5-4d01-854b-c2255130c39b%40googlegroups.com</a>.<br> </blockquote></div>